1. Field of Invention
The present invention relates to small internal combustion engines such as those used with lawnmowers, lawn tractors, and other lawn and garden implements. In particular, the present invention relates to a new recoil starter for such engines.
2. Description of the Related Art
Typically, implements with small internal combustion engines include a manually-operable recoil starter for engine starting. The recoil starter includes a handle and rope pull assembly which is manually pulled by an operator to rotate the flywheel and crankshaft in order to begin reciprocation of the piston as well as actuation of the ignition assembly to start the engine.
The pulleys of prior recoil starters are usually restrictive in the center to airflow, allowing only an annular air opening around the outer recoil region. The pulley construction necessitates that air entering the engine must be directed around the pulley, thus the pulley restricts airflow into the engine. To compensate for the restricted airflow, prior methods, such as elevating the pulley assembly to create a small area for air to enter beneath the pulley, were implemented. However, the engines which incorporate these methods may still experience restricted airflow since a maximum amount of air is not drawn into the engine through the small area.
What is needed is a recoil starter having a construction which allows a maximum amount of air to easily enter the engine for improved engine cooling.
A centerless recoil starter is provided which is used with a small internal combustion engine having a blower housing, a flywheel, and a crankshaft. The centerless recoil starter generally includes an annular cover mounted to the blower housing and defining an airway into the blower housing and the engine and also includes an annular starter mechanism for engaging the flywheel, thereby rotating both the flywheel and the crankshaft to start the engine.
The annular starter mechanism for engaging the flywheel includes an annular ring within a track around the airway having engagement elements, such as pulley dogs, therein to engage posts on the flywheel. The pulley dogs have a retracted position during normal engine operation and an extended position for engaging the posts during engine starting. Also included is a spring which retracts the rope and pulley thus causing the pulley dogs to rotate back to their retracted position.
An advantage of the inventive recoil starter is that airflow to the engine is unrestricted. With the recoil starter having a substantially open center, air is freely able to enter the blower housing and the engine to provide less restrictive airflow to the engine.
The present invention provides an internal combustion engine, including a crankcase having a crankshaft rotatably disposed therein, a flywheel mounted to the crankshaft externally of the crankcase, a blower housing attached to the crankcase and having an opening disposed generally above the flywheel, and an annular recoil starter mechanism attached to the blower housing and disposed around the opening to define a center airway therethrough into the blower housing. The annular recoil starter mechanism selectively engages the flywheel to rotate the flywheel and the crankshaft to start the engine.
The present invention further provides an internal combustion engine, including a crankcase having a crankshaft rotatably disposed therein, a flywheel mounted to the crankshaft, a blower housing attached to the crankcase, and an annular recoil starter mechanism attached to the blower housing and disposed around an opening in the blower housing generally above the flywheel.
The present invention also provides an implement having a small internal combustion engine including a frame, an engine connected to the frame and having a crankshaft disposed therein, a flywheel mounted to the crankshaft, and an annular recoil starter mechanism attached to the housing and disposed around an opening in the housing generally above the flywheel.